Chair construction employing tension-held slats



y 1957 j R. F. DREIFKE 2,798,538

CHAIR CONSTRUCTION EMPLOYING TENSI ON-HELD SLATS Filed Aug. 18, 1954 INVENTOR RAYMOND ,F. DREIFKE I T BY 7 1 i \37 FIG. 7 ATTORNEY United rates CHAIR CONSTRUCTION EMPLOYING TENSION-HELD SLATS Raymond F. Dreifke, St. Louis, Mo.

Application August 18, 1954, Serial No. 450,595

9 Claims. (Cl. 155-187) This invention relates to chair construction, and particularly to a form of chair employing tension-held slats in the seat and back thereof.

The objects of the present invention include:

Providing a seat and back structure which is readily assembled to and disassembled from a legged base;

Providing for the easy assembly of. slatted seat and back structures, with provision for varying the arrangement of slats of dilferent tones and wood grains to meet the taste of the owner;

Providing a degree of resiliency at the side of the seat structure to increase its comfort when a person sits side ward on it;

Providing resilient inserts for seat slats cut from solid pieces of wood; and

Providing a method of cutting curved seat and back slats out of straight pieces of wood with economy of both labor and material.

The foregoing objects and others will be apparent from the detailed description which follows.

In the drawings (one sheet) Figure 1 is a front elevation of a chair constructed in accordance with and embodying the present invention.

Figure 2 is a side sectional View taken along line 22 of Figure 1.

Figure 3 is an enlarged fragmentary section taken along line 3--3 of Figure 2.

Figure 4 is a similarly enlarged fragmentary section taken along line 44 of Figure 2.

Figure 5 is a view similar to Figure 4 showing an alternative structure including resilient tubular inserts within bores in the wooden seat slats.

Figure 6 is a cabinet projection illustrating the manner of cutting two similar curved seat slats from a single short straight piece of wood.

Figure 7 is a cabinet projection illustrating the method of cutting back slats, said figure being otherwise similar to Figure 6.

Referring to Figures 1 and 2, there is shown a base structure generally designated 10, comprising a pair of front legs 11 and a pair of rear legs 12, each leg being canted outward from one of the four radially-extending spider leg-support members 13 to which it is securely welded. The spider members 13 converge centrally downward to a central mount point 14, penetrated by an upward-extending hook 15, the hook having at its lower extremity a washer 16 and a thumb nut 17. Such base structures are adapted for stacking with each other, thus facilitating shipment and storage.

The chair seat and back illustrated have a common central structural member which extends along the chairs plane of symmetry, aft beneath the seat surface and thence upward behind the back surface. It is designated as the spine 18, preferably formed of a bent steel rod, and it supports all the seat and back slats, hereinafter described, on centilevered ribs welded transversely across it.

The ribs referred to include the forward seat rib 19,

a bowed rod welded to the forward end of the spine 18 and extending somewhat curvingly upward on both sides of the plane of symmetry; a similarly bowed aft seat rib 20, welded to the upper surface of the spine at the inner side of the spines upward bend; the lower back rib 21, welded to the forward side of the upward-extending portion of the spine 18 and bowed slightly upward as shown in Figure 1; and the upper back rib 22 welded to the upper aft end of the spine 18 and having a bowed shape substantially corresponding to the bow of the lower back rib 21. All the said ribs are cantilevered from the spine 18, and held by rigid welds 23. In the embodiment illustrated, the lower back rib 21 is slightly longer than the upper back rib 20; and both are curved slightly upward.

Between the forward seat rib 19 and the aft seat rib 20 the spine 18 has a bend to lower it below the surface of the slat members hereinafter described, so as to be readily grasped by the hook 15 of the base structure 10.

Along each side of the spine 18, and supported on aligned lateral bores spaced to accommodate the seat ribs 19, 20, are a plurality of spaced seat slats 24. Each has a curved upper surface 25 hereinafter described, and a substantially flat lower surface 26. Each is penetrated by a forward lateral bore 27 and an aft lateral bore 28, of sufficient diameter to permit easy mounting upon the cantilevered ribs 20, 21. The seat slats 24 are held separated from each other by preferably resilient separator washers 29 which may be cut from thick-walled rubber tubing.

Back slats 30 are similarly mounted in alignment with each other on each side of the upwardly-extending rear portion of the spine 19, and these also are preferably separated from each other by separator washers 29. In order to effect a tapered or fan-like appearance of the back construction, the resilient separator washers are omitted from the upper back rib 22.

The slats 24, 30 may be cut of woods having different grains varying in tone; or may be formed of other materials of different colors and textures. In such event, the owner may readily arrange such slats according to his own taste.

Each seat slat 24 has a small lateral tension wire bore 31 extending through it at a point between the forward lateral bores 27 and the aft lateral bores 28, the said tension wire bores 31 being in alignment with each other. Each ,back slat 30 has a similar tension wire bore 31 located in alignment at some point between the lower back rib 21 and the upper back rib 22. Through such aligned tension wire bores extend the seat tension wire 32 and the back tension wire 33, threaded at each end to engage a hollow screw 34 by which tight adjustment is secured. Tension exerted by the heads of the screws 34 against the outermost of the seat slats 24 and back slats 39 hold all slats securely in place on the ribs 19, 20, 21, 22.

After the seat slats 2.4 and back slats 30 are mounted onto the ribs 19, 20, 21, 22, the spine 18 is hooked to the base structure. The seat structure described is assembled to the base structure 10 by grasping the spine 18 with the hook 15. It will be seen that the outer ends of the spider members 13 press upward against the said slats 24 which overlay them, thus affording secure attachment with only the single central hook 15.

Referring to Figures 1, 3 and 4, the seat structure is obviously capable of a substantial degree of elastic bending, particularly the side portion outboard of that seat slat 24 which is fourth from the spine 18.. This is of importance if the chair is used for lounging or sitting sidewards. If body weight be exerted near the outer side of the chair, the forward seat rib 19 and aft seat rib 20 will tend to bend elastically, somewhat flattening the outer side portion of the seat. Accordingly, even though the seat ribs 19, 20 are bowed up considerably, the seat will be comfortable if a person sits sideward across it.

While each of the seat slats 24 may be identical, it may be desired, for purpose of more attractive side appearance, to use special end seat slats 35, one of which is shown in.Figure 4. The shape of the end seat slats 35 is in .general similar to the other seat slats 24 but their contour at their outer side edges maybe rounded as shown in Figure 4, or otherwise varied at pleasure. No lateral bores penetrate the end. slat 35 completely; instead, partial bores 36, such as shown in Figure 4, penetrate deeply enough to accommodate and give clearance to the outer ends of the seat ribs 19, 20. The end slats of the back construction may be similarly modified.

In order to make the seat construction somewhat more resilient, a modified form of invention is shown in Figure 5. Seat slats 24 are formed with somewhat enlarged lateral rib-accommodating aft bores 28 and similarly enlarged forward lateral bores, not shown. Into each bore, there is assembled a resilient bushing 37, such as may be formed by cutting a soft rubber'tube to appropriate length. The use of bushings 37 allows resilient deflection of the seat slats 24.

Among the objects of the present invention is the utilization of materials with economy, as well as ease of construction. Figure 6 illustrates how seat slats 24 may be readily cut, as by band sawing, from straight strips of lumber; and Figure 7 shows how the back slats 30 are cut. For the seat slats 24, an elongated, substantially rectangular strip of lumber 38, of requisite width and length, is utilized for two mating slats. A center is found on the side surface of the strip 38, and a line marking the midpoint of depth may be drawn if desired; for reference, see center 39 and mid-depth line 40 on each of Figures 6 and 7. It is seen from Figure 6, as well as from Figure 2, that the lateral bores 27, 28 which mount the seat slats 24, are through sections of greater-thanaverage depth; similarly in Figure 7, the mounting bores of the back slats 30 are through sections of greater-thanaverage depth. It is also seen that the curved upper surface 25 of each mating seat slat 24 is a common line. Waste portions, shown at the corners, are small.

' The line of division which forms the curved surface 25 of each of the mating seat slats 24 has a point of inflection at the center 39 of the strip 38, and it crosses the mid-height of the strip at least once at each side of the center 39. This is also seen to be true in the case of cutting the back slats 3% as shown in Figure 7. In order that the mating slats be identical with each other, the pattern of the curved line on each side of the center point'of inflection is similar to and 180 removed from the portion on the other side of said center point of inflection. The lateral bores 27, 28 on which the seat slats 24 are supported may be drilled prior to dividing such mating seat slats. As to each individual seat slat 24, the bores 27, 28 lie on opposite sides of such center point of inflection 39. This is likewise true of the bores which support the back slats 30, as may be seen from Figure 7.

Referring to Figure 2, the contour of the seat structure, when unhooked from the base structure, permits the close stacking of the chair seats and backs with each other, in a minimum of space. It has been noted that the leg structures. shown also stack neatly.

The chair construction herein illustrated is capable of substantial variation without departing from the teachings of the invention. The contour and-proportions of both seat and back slats may be substantially varied; upholstery may be added; etc. Furthermore, different forms of base structure may be utilized, for example, pedestal, swivel or castering bases. Accordingly, the specification and claims hereof are not to be interpreted narrowly, but as fully co-extensive with the inventive principles, herein disclosed.

I claim:

1. In the construction of chairs and the like, a spine member, a rib member cantilevered from said spine member so as to extend transversely to both sides thereof, a plurality of body-support members mounted on said rib member on each side of the spine member and a tension tie extending across the spine member and securing the body support members toeach other.

2. Chair construction as set forth in claim 1, together with a leg frame work, and means for securing said spine member to said leg framework.

3. In chair construction symmetrical on both sides of a central vertical plane, seat structure comprising a spine member extending in said plane of symmetry immediately below the level of the center of the seat, parallel lateral seat ribs supported at their mid-point by the said spine member, a plurality of seat slats supported by said seat ribs, each said slat having lateral bores corresponding in number and spacing to the number and spacing of said seat ribs and of sufiiciently large size to fit over said ribs, and securement means whereby said seat slats are held in place.

4. Seat structure as defined in claim 3, the slat securement means comprising a tension tie extending beneath the seat surface between the outer ribs on the opposite sides of the spine member and exerting compression against the outer slats.

5. Seat structure as defined in claim 3, the said seat ribs having outer portions cantilevered, bowed upward and possessing appreciable resiliency under body weight, together with chair base structure supporting said seat structure inward of the said outer portions of said seat ribs, whereby the said outer portions of said seat ribs may deflect under body weight and thereby provide a flatter seat portion on whichever side of center the greater part of the body weight is concentrated.

6. Seat construction as defined in .claim 3, the lateral bores in the seat slats having resilient tubular liners hearing upon the ribs.

7. Seat construction as defined in claim 3, together with washer-like separators mounted on said ribs alternately between the seat slats, the said securement means being an adjustable tension tie adapted to exert compression against said washer-like separators.

8. Seat construction as defined in claim 3, together With a support framework having legs, an upward projecting hook arranged substantially at the center of the pattern of said legs, and take-up means for tightening said hook, the said hook being adapted to engage the spine member at a level beneath the seat surface.

9. Seat structure as defined in claim 3, together with a support framework having a plurality of seat support points adapted to bear upwardly against such seat structure outwardly of its center, and a central hook adapted to engage the spine and apply downward force thereto, whereby to secure the seat structure firmly to the supporting framework.

References Cited in the file of this patent UNITED STATES PATENTS Crawford .Tune 1, 1948 

